Method and apparatus for inter-layer residue prediction for scalable video

1. An apparatus, comprising: an encoder for encoding a block of a picture using an encoding process, wherein the encoding process comprises applying inverse tone mapping to inter-layer residue prediction for the block, wherein the inverse tone mapping is performed in the pixel domain, and wherein the encoder includes: a motion compensator; a tone mapper directly coupled to said motion compensator; a combiner directly coupled to said tone mapper; a spatial upsampler directly coupled to said combiner; an inverse tone mapper coupled to said combiner, and wherein said encoder performs the inter-layer residue prediction process by said motion compensator performing motion compensation in an enhancement layer of the picture to obtain an enhancement layer prediction, said tone mapper performing tone mapping on the enhancement layer prediction into a base layer of the picture to obtain a tone mapped motion compensated low bit depth prediction for the block, said combiner adding a spatially upsampled residue from the base layer to the tone mapped motion compensated low bit depth prediction for the block to obtain a sum, and said inverse tone mapper performing the inverse tone mapping on the sum into the enhancement layer to obtain a higher bit depth prediction for the block.

2. The apparatus of claim 1 , wherein said encoder further performs the inter-layer residue prediction process by applying a smoothing filter to the sum prior to performing the inverse tone mapping, and wherein the inverse tone mapping is performed on the filtered sum.

3. The apparatus of claim 1 , wherein at least one of a high level syntax element and a block level syntax element is used to signal any of the tone mapping and the inverse tone mapping.

4. The apparatus of claim 3 , wherein the high level syntax element is comprised in at least one of a slice header, a sequence parameter set, a picture parameter set, a view parameter set, a network abstraction layer unit header, and a supplemental enhancement information message.

5. The apparatus of claim 1 , wherein said encoder further performs the inter-layer residue prediction process by subtracting an error value from the higher bit depth prediction for the block wherein the said error value is between the signal values obtained from the tone mapping and inverse tone mapping.

6. The apparatus of claim 1 , wherein the inverse tone mapping is performed in the pixel domain to support bit depth scalability.

7. A method, comprising: encoding a block of a picture, wherein said encoding step comprises applying inverse tone mapping to inter-layer residue prediction process for the block, wherein the inverse tone mapping is performed in the pixel domain, and wherein the inter layer residue prediction comprises: performing motion compensation in an enhancement layer of the picture to obtain an enhancement layer prediction; performing tone mapping on the enhancement layer prediction into a base layer of the picture to obtain a tone mapped motion compensated low bit depth prediction for the block; adding a spatially upsampled residue from the base layer to the tone mapped motion compensated low bit depth prediction for the block to obtain a sum; and performing the inverse tone mapping on the sum into the enhancement layer to obtain a higher bit depth prediction for the block.

8. The method of claim 7 , wherein the inter layer residue prediction process further comprises applying a smoothing filter is applied to the sum prior to said step of performing the inverse tone mapping, and wherein the inverse tone mapping is performed on the filtered sum.

9. The method of claim 7 , wherein at least one of a high level syntax element and a block level syntax element is used to signal any of the tone mapping and the inverse tone mapping.

10. The method of claim 9 , wherein the high level syntax element is comprised in at least one of a slice header, a sequence parameter set, a picture parameter set, a view parameter set, a network abstraction layer unit header, and a supplemental enhancement information message.

11. The method of claim 7 , wherein the inter layer residue prediction process further comprises subtracting an error value from the higher bit depth prediction for the block wherein the said error value is between the signal values obtained from the tone mapping and inverse tone mapping.

12. The method of claim 7 , wherein the inverse tone mapping is performed in the pixel domain to support bit depth scalability.

13. A non-transitory computer-readable storage media having video data encoded thereupon, comprising: a block of a picture encoded by an encoding process that comprises applying inverse tone mapping to interlayer residue prediction process for the block, wherein the inverse tone mapping is performed in the pixel domain, and wherein the inter layer residue prediction comprises: performing motion compensation in an enhancement layer of the picture to obtain an enhancement layer prediction; performing tone mapping on the enhancement layer prediction into a base layer of the picture to obtain a tone mapped motion compensated low bit depth prediction for the block; adding a spatially upsampled residue from the base layer to the tone mapped motion compensated low bit depth prediction for the block to obtain a sum; and performing the inverse tone mapping on the sum into the enhancement layer to obtain a higher bit depth prediction for the block.